Journal of Volcanology and Geothermal Research最新文献

{"title":"The fatal 9th December 2019 eruption disaster on Whakaari/White Island volcano, New Zealand: Contributing factors, failures, and lessons for volcano tourism","authors":"Raymond A.F. Cas","doi":"10.1016/j.jvolgeores.2025.108461","DOIUrl":"10.1016/j.jvolgeores.2025.108461","url":null,"abstract":"<div><div>The eruption of Whakaari/White Island volcano in New Zealand on 9th December 2019 resulted in 22 deaths of tourists and tour guides and 22 seriously injured survivors. The key factors that contributed to the disaster were the dangerous, unpredictable and frequently explosive state of the volcano, the very active hydrothermal system under the crater, its eruption phenomena, the remote oceanic setting, allowing tourists and tour guides to go into the amphitheatre-like crater right up to the active vent, totally inadequate information for tourists on how dangerous and potentially deadly the volcano could be, and the procedural and regulatory failures of many organisations that should have ensured that volcano tourism was conducted and managed in a responsible and safe way. These include the volcanological monitoring agency GNS, national WorkSafe New Zealand, national and regional emergency response authorities, including police and defence forces, national and regional tourism organisations, adventure tourism companies, and indirectly even the national public liability insurance organisation. This overview of what went wrong highlights that even in developed countries, failure to enforce safety regulations embedded in national laws, a catastrophic failure in communication between organisations, conflicts of interest, and the consideration of economic impacts on tourism in decision making during volcanic crises can lead to disasters in volcano tourism. The disaster reveals important lessons for volcano tourism both in New Zealand and globally.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"468 ","pages":"Article 108461"},"PeriodicalIF":2.3,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145221843","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the transport of CO2 and Radon in the geothermal area of Acoculco, Puebla, Mexico","authors":"Fernando J. Guerrero ,&nbsp;Daniel Pérez-Zárate ,&nbsp;Edgar Santoyo ,&nbsp;Adrián Jiménez-Haro ,&nbsp;David Yáñez-Dávila ,&nbsp;Gustavo Santos-Raga","doi":"10.1016/j.jvolgeores.2025.108451","DOIUrl":"10.1016/j.jvolgeores.2025.108451","url":null,"abstract":"<div><div>We present a conceptual and numerical description of CO<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> and Radon (²²²Rn) transport in the geothermal system of Acoculco, Mexico. We build upon extensive CO<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> flux measurements that have been conducted in the past and new CO<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> flux and Rn concentration data collected during this investigation. The accumulation chamber method was employed for CO<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> flux measurements, whereas Rn concentration derives from analysis of gas samples collected in active scintillation cells. Additionally, the structural setting in the study area is reinterpreted based on a geomorphological assessment. As a result, a 3D conceptual model of the CO<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> and Rn is proposed and numerically modeled with the aid of TOUGHREACT V4. Our collected data confirm the existence of advective transport of CO<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> and Rn within two sites known as Azufres and Alcaparrosa, with soil CO<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> fluxes that can reach 30,000 g m⁻²day⁻¹, and Rn concentrations as high as <span><math><mo>∼</mo></math></span>12,000 Bq/m<span><math><msup><mrow></mrow><mrow><mn>3</mn></mrow></msup></math></span>. In view of the relatively short half-life of ²²²Rn (<span><math><mo>∼</mo></math></span>3.8 days), the measured concentrations are indicative of localized permeable paths that connect with deep structures. Our numerical model represents adequately the non-isothermal diffusive transport of CO<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>, while advective fluxes are not attained under simple darcian flow. Likewise, under a hypothesis of a deep Rn source (<span><math><mo>∼</mo></math></span>1200 m), with an initial molar ratio Rn/CO<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> of 1<span><math><mrow><mo>×</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>4</mn></mrow></msup></mrow></math></span>, Rn concentrations drop rapidly (within <span><math><mo>∼</mo></math></span>100 m from the source). Non-porous flow (channeling) and distributed sources of Rn arise as likely hypotheses to explain cold degassing in Acoculco.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"468 ","pages":"Article 108451"},"PeriodicalIF":2.3,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145221881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Middle–to–late Holocene explosive eruptions of Lonquimay volcano (Southern Andes of Chile): Stratigraphy, tephra dispersal, and pre-eruptive conditions","authors":"Jorge E. Romero ,&nbsp;Francisco Cáceres ,&nbsp;Luis Rojas ,&nbsp;Alicia Guevara ,&nbsp;Edmundo Polanco ,&nbsp;Francisca Vergara-Pinto ,&nbsp;Eleni Michailidou ,&nbsp;José A. Naranjo ,&nbsp;Alessandro Fabbrizio ,&nbsp;Gregor Weber ,&nbsp;Jorge Bustillos ,&nbsp;Ángelo Castruccio ,&nbsp;Matías Poblete ,&nbsp;Inés Rodríguez","doi":"10.1016/j.jvolgeores.2025.108457","DOIUrl":"10.1016/j.jvolgeores.2025.108457","url":null,"abstract":"<div><div>The Lonquimay-Tolguaca Volcanic Complex (LTVC), located in Chile's Andean Southern Volcanic Zone (40°S), experienced its last eruption in 1988–90, profoundly affecting neighbouring rural communities. Yet, more than twenty explosive eruptions have been recognised and described at Lonquimay volcano from its Holocene tephra records. Knowing its eruptive past is one of the main concerns of the residents of Malalcahuello, 11 km <em>E</em>-SE from the LTVC. In this contribution, we aim to decipher the behaviour of Lonquimay, focusing on its most recent (i.e., Middle-to-Late Holocene, &lt;5.5 ka) explosive history to address community-based questions with renewed scientific knowledge. We studied proximal-to-medial (i.e., 2–15 km) tephra sequences east-southeast from the LTVC. Seventeen tephra units were described. These are mainly formed by rhythmic alternations of both grey to white pumice beds, and black to brown scoria beds. Pyroclast textures consisting of scoria, dense juvenile fragments and pumices display compositions ranging from basalts to dacites. The study of tephra deposits suggests Strombolian to Sub-Plinian eruptive styles, whereas isopach-based volume estimates on the order of 10⁷ m³ from four individual deposits support a Volcanic Explosivity Index (VEI) of 3. This type of events has a 27–61 % probability of occurrence within the next 100 years. The studied tephra deposits were fed by mafic (basaltic and basaltic andesitic, 1050–1100 °C) and silicic (andesites and dacites, 890–940 °C) magma batches stored between ∼2 to ∼7.5 kbar. Magma evolution was mostly controlled by fractional crystallisation and occasional mixing events. Assessing tephra fall deposits simultaneously at multiple scales offers clues on the eruptive scenarios, magma processes and sources, as well as potential hazards of their parent volcanic systems. Along with contributing to scientific knowledge, these elements can enhance risk reduction strategies by integrating community questions about active volcanism into hazard research.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"468 ","pages":"Article 108457"},"PeriodicalIF":2.3,"publicationDate":"2025-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145221845","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Contrasting magmatic structures and tectonic controls from integrated gravity and magnetic data in the Bromo–Tengger–Semeru complex and the Lamongan Volcanic Field, East Java, Indonesia","authors":"Khalil Ibrahim ,&nbsp;Satria Bijaksana ,&nbsp;Mirzam Abdurrachman ,&nbsp;David Prambudi Sahara ,&nbsp;Putu Billy Suryanata ,&nbsp;Sitti Zulaikah ,&nbsp;Rezki Wirawan ,&nbsp;Ulvienin Harlianti ,&nbsp;Thomas Andre Maris Widagdo ,&nbsp;Silvia Jannatul Fajar ,&nbsp;Yohansli Noya ,&nbsp;Ni Komang Tri Suandayani","doi":"10.1016/j.jvolgeores.2025.108455","DOIUrl":"10.1016/j.jvolgeores.2025.108455","url":null,"abstract":"<div><div>This study aims to clarify how contrasting tectonic regimes influence magma storage, connectivity, and emplacement in spatially adjacent volcanic systems within a single arc segment in East Java, Indonesia. We focus on the polygenetic Bromo–Tengger–Semeru (BTS) complex and the Lamongan Monogenetic Volcanic Field (LMVF), employing integrated gravity and magnetic approaches including Bouguer anomaly modeling, 3D Euler and 2D Werner deconvolution, constrained gravity inversion, and magnetic edge detection. A vertically extensive, lens-shaped high-density body is imaged beneath BTS between 5 and 20 km depth, with indications of lateral connectivity between Semeru and Bromo aligned along N-S compressional structures. In contrast, LMVF shows only shallow, dyke-like intrusions (&lt;2.5 km) aligned with NW–SE and NE–SW faults, spatially correlated with maar lakes and cinder cones. These findings support a model in which compressional tectonics in BTS promote deep, laterally connected magma reservoirs, while extensional faulting in LMVF facilitates shallow, structurally guided intrusions. This comparative analysis highlights the role of tectonic segmentation in shaping magmatic structure and provides a replicable framework for integrated geophysical analysis of arc volcanism.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"468 ","pages":"Article 108455"},"PeriodicalIF":2.3,"publicationDate":"2025-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145221842","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Postglacial effusive activity at Mt Ruapehu, Aotearoa New Zealand: Lava flow volumes and eruptive rate","authors":"Pedro Doll ,&nbsp;Ben Matthew Kennedy ,&nbsp;Alexander Robert Lee Nichols ,&nbsp;Jim William Cole ,&nbsp;Dougal Bruce Townsend ,&nbsp;Shaun Robert Eaves ,&nbsp;Chris Edward Conway ,&nbsp;Graham Sloan Leonard ,&nbsp;Jonathan Davidson","doi":"10.1016/j.jvolgeores.2025.108435","DOIUrl":"10.1016/j.jvolgeores.2025.108435","url":null,"abstract":"<div><div>Hazards posed by volcanic eruptions are directly related to the frequency and magnitude of eruptions, and understanding these parameters for past events helps to assess future hazards associated with individual volcanoes. Ruapehu (Aotearoa New Zealand) is an andesitic stratovolcano that produced several dozens of lava flows and tephra units during the last 20 kyr, and has been affected by two flank collapses during the Early and Middle Holocene. Recent studies have significantly improved the chronology of young (&lt;20 ka) lava flow forming eruptions, but the magnitude of these events remain poorly constrained. In this study, we estimate the volume of 52 young lava flows at Ruapehu, and combine this data with a compilation of all available chronological constraints and published volumetric and chronological data of pyroclastic eruptions, to produce a detailed cumulative erupted volume curve for the last 20 kyr at Ruapehu. After the emplacement of large lava flows during the end of the Last Glacial Maximum (LGM), the eruptive rate remained relatively constant at around 0.27 km³/kyr (dense rock equivalent or DRE) until ca. 7.4 ka. Then, activity ceased for c. 2 kyr, after which it resumed less intensely than before 7.4 ka and from the southern vent only. Our data suggests that the two Holocene flank collapses that affected Ruapehu’s summit area have had different effects on the plumbing and magmatic system; the larger Early Holocene collapse forced a change in eruptive style towards effusive eruptions, while the smaller Mid-Holocene collapse did not have a significant impact on the volcanic activity. This study shows the importance of robust volumetric and chronological analyses in providing insights on the evolution of stratovolcanoes, and particularly when analysing the causes of the temporal variability of their activity.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"468 ","pages":"Article 108435"},"PeriodicalIF":2.3,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145221844","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seismic imaging of mid-crustal heterogeneity beneath geothermal systems, central Taupō Volcanic Zone, New Zealand","authors":"Stephen Bannister ,&nbsp;Edward A. Bertrand ,&nbsp;Geoff Kilgour ,&nbsp;T. Grant Caldwell ,&nbsp;Isabelle Chambefort ,&nbsp;Wiebke Heise ,&nbsp;Sandra Bourguignon","doi":"10.1016/j.jvolgeores.2025.108448","DOIUrl":"10.1016/j.jvolgeores.2025.108448","url":null,"abstract":"<div><div>The Taupō Volcanic Zone (TVZ) in New Zealand is a region of highly productive Quaternary volcanism and high hydrothermal heat flux. We investigate the mid-crustal seismic velocity structure of a region within the central, rhyolitic part of the TVZ encompassing high-temperature geothermal systems (e.g. Wairakei, Rotokawa). Using double-difference tomographic inversion of local earthquake data we derive 3-D models of P-wave velocity (<em>Vp</em>) and <em>Vp/Vs</em> for the subsurface. Both high (<span><math><mo>&gt;</mo></math></span> 6.0 km/s) and low (<span><math><mo>&lt;</mo></math></span> 5.5 km/s) <em>Vp</em> heterogeneities are seen in the mid-crust between 5 and 11 km depth. Regions with high <em>Vp</em> are interpreted to indicate the presence of solidified, more mafic, material within an otherwise quartzo-feldspathic crust, while regions with low <em>Vp</em> values are inferred to represent bodies of crystal-rich magma with a low melt fraction. Using the new 3-D velocity model we then relocated <span><math><mo>∼</mo></math></span>9100 earthquakes recorded between 2009 and 2022. The relocated seismicity is strongly clustered, including in the vicinity of some of the geothermal systems (e.g. Rotokawa) where fluid is currently being extracted for electric-power production. Mid-crustal seismicity is also observed west of the Wairakei geothermal field, as well as along the south-eastern margin of the Ngakuru graben and on the western margin of the Whakamaru caldera. The depth distribution of the highest-quality hypocentres shows that 90% of the seismicity at Rotokawa geothermal field occurs at depths shallower than 5.1 km, consistent with a shallow brittle–ductile transition and the presence of a cooling pluton beneath Rotokawa seen in magnetotelluric data.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"468 ","pages":"Article 108448"},"PeriodicalIF":2.3,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145159448","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evolution of the Galeras Volcanic complex, SW Colombia: An updated version of the stratigraphy and geological map","authors":"Mauricio Tamayo ,&nbsp;Silvia C. Castilla ,&nbsp;Lorena Rayo ,&nbsp;Bernardo Pulgarín ,&nbsp;Diego Palechor ,&nbsp;Edwin Villamil ,&nbsp;Ana María Correa-Tamayo ,&nbsp;Yeni Cruz-Toro ,&nbsp;Indira Zuluaga ,&nbsp;Luisa Acosta ,&nbsp;Santiago Villota ,&nbsp;Johana Gómez ,&nbsp;Paola Naváez ,&nbsp;Estefania Castellanos","doi":"10.1016/j.jvolgeores.2025.108449","DOIUrl":"10.1016/j.jvolgeores.2025.108449","url":null,"abstract":"<div><div>The Galeras Volcanic Complex (GVC) is one of the most active centers in the southern Colombian Andes. In this study, we present an updated version of the GVC geological map by integrating field observations with existing literature, new Ar/Ar and ¹⁴C geochronology, petrography, geochemistry, and remote sensing analyses. Our revised stratigraphic scheme combines lithostratigraphic units (as the basic mapped units) into informal lithosomes (representing the main eruptive centers), with interpretations of the volcanological sequence in terms of eruption units (e.g., fallout, pyroclastic density current, block-and-ash flow) and volcanic activity units (e.g., period, epoch, eruption, phase, pulse), which are fundamental for understanding the volcanic evolution of the GVC throughout its history.</div><div>The GVC is an andesitic to basaltic andesitic volcanic complex consisting of five overlapping stratovolcanoes: Cariaco, Coba Negra, Genoy, Urcunina, and Galeras; as well as one adventive cone known as La Guaca located southwest of the complex. Only remnants of the oldest Cariaco edifice, formed between 1440 ± 163 and 1249 ± 279 ka, are preserved to the west. Progressive vent migration eastward led to the formation of the Coba Negra (1138 ± 30 ka – 406 ± 3.2 ka) and Genoy (364 ± 47 ka to ∼9 ka) structures, controlled by lateral collapses under structural influence. Monogenetic activity southwest of the complex is recorded by basaltic lava flows dated at 900 ka and 185 ka, as well as the La Guaca scoria cone. Urcunina, smaller than the previous edifices, was the last eruptive center (∼7.5–0.9 ka) before the current active cone. Similar to Coba Negra and Genoy, the summit of Urcunina is truncated by a volcano-tectonic collapse scar, representing a proximal unconformity that, along with its related disconformities in medial to distal zones, indicates volcanic quiescence. Renewed eruptions occurred in approximately the same vent position, filling the upper part of the Urcunina tectonic depression and forming the active Galeras cone. Holocene activity has been dominated by dome-building events, lava flows, Strombolian activity, and minor to moderate vulcanian eruptions, often destroying domes partially or completely. Deposits from historical eruptions are primarily found around the summit and upper parts of the Urcunina collapsed scar. The volcano is considered active based on current seismic activity, gas emissions through fumaroles, hot springs, and the eruptive activity recorded from 1989 to 2013.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"468 ","pages":"Article 108449"},"PeriodicalIF":2.3,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145221214","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The 1990's thermal crisis at La Fossa volcano (Aeolian Islands, Italy): Systematics of magmatic vapor plume expansion and decay within an active volcano","authors":"Paolo Fulignati ,&nbsp;Anna Gioncada ,&nbsp;Alessandro Aiuppa ,&nbsp;Terry M. Seward ,&nbsp;Richard W. Henley","doi":"10.1016/j.jvolgeores.2025.108450","DOIUrl":"10.1016/j.jvolgeores.2025.108450","url":null,"abstract":"<div><div>The La Fossa cone on Vulcano island (Italy), like most active volcanoes, undergoes periodic phases of increased heat and gas discharge unrelated to surface magmatism. Variations in the major component chemistry of fumaroles during such cycles record the expansion and contraction of a magmatic vapor plume beneath the volcano in response to cycles of mafic magma intrusion several km below the surface and consequent changes in its interaction with surrounding meteoric water/seawater.</div><div>Using previously unpublished major and minor element fumarole data for the 1990's thermal crisis at La Fossa in conjunction with a primary mafic magma vapor composition derived from melt inclusion data and silicate melt-vapor partition coefficients, a thermochemical equilibrium model is developed to explain variations in fumarole gas chemistry in terms of subsurface gas-solid reactions during magmatic vapor expansion and dilution from source to surface. These reactions control total S and H₂ through the production of anhydrite (CaSO₄) and sulfide minerals. Pyrite, bismuthinite and sphalerite deposition, control the minor element composition of fumarole discharges. Most of the Cu is deposited as CuFe sulfides in the core of the expanding vapor plume so that it is not observed at surface. As is observed in fumarole sublimates, Au is deposited at low pressure in response to removal of H₂S by sulfide deposition.</div><div>The thermochemical modelling results coupled with fumarole sublimate compositional data provide a metal zonation model for the interior of La Fossa that may be considered generic for other active volcanoes and their ancient equivalents.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"468 ","pages":"Article 108450"},"PeriodicalIF":2.3,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145159452","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Gas emissions from the Sulphur Bank Mercury Mine hydrothermal system, Clear Lake volcanic field, California","authors":"Jennifer L. Lewicki ,&nbsp;Sara Peek ,&nbsp;Laura E. Clor ,&nbsp;Andrew G. Hunt","doi":"10.1016/j.jvolgeores.2025.108453","DOIUrl":"10.1016/j.jvolgeores.2025.108453","url":null,"abstract":"<div><div>The Sulphur Bank Mercury Mine (SBMM) hydrothermal system offers insights into active degassing processes in the Clear Lake volcanic field (CLVF), a high-threat region based on its record of Holocene eruptions and proximity to populated areas. Here we present chemical and isotopic analyses of gas samples collected between 2015 and 2023, along with the first comprehensive CO₂ flux survey of the SBMM area conducted in 2023. Sampled gases are CO₂- and CH₄-rich (≥84 and 6 mol% in dry gas, respectively) with high mantle-derived helium contributions (³He/⁴He = 6.54–7.86 R_C/R_A). Carbon isotopic compositions of CO₂ (δ¹³C = −10.0 to −9.5 ‰) and CH₄ (δ¹³C = −35.8 ‰) indicate mixed sources, with significant contributions from metamorphism of organic-rich Franciscan Complex rocks hosting the hydrothermal system. Modeling of gas compositions shows that scrubbing by interaction with air-saturated groundwater strongly influences observed compositional variability. From our CO₂ flux measurements, we estimate the deeply derived CO₂ emission rate from the SBMM hydrothermal area (0.2 km²) at 240 t d⁻¹, comparable to many quiescently degassing volcanoes worldwide. We also provide a first-order estimate of CH₄ emissions at approximately 0.5 t d⁻¹. Our findings establish crucial baseline data for future volcanic monitoring efforts, enhancing detection capabilities for potential changes in this active hydrothermal system. This work contributes to the broader understanding of volatile contributions from volcanic and metamorphic sources to the global carbon budget, while highlighting the strong influence of bedrock geology on gas compositions in the CLVF.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"468 ","pages":"Article 108453"},"PeriodicalIF":2.3,"publicationDate":"2025-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145159449","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tracking changes in the tremor sources associated with a Gorely Volcano degassing episode in 2013","authors":"Yaroslav Berezhnev ,&nbsp;Nadezhda Belovezhets ,&nbsp;Nikolai M. Shapiro ,&nbsp;Sergei Abramenkov ,&nbsp;Ivan Koulakov","doi":"10.1016/j.jvolgeores.2025.108452","DOIUrl":"10.1016/j.jvolgeores.2025.108452","url":null,"abstract":"<div><div>Gorely, one of the most active volcanoes in Kamchatka, experienced a long period of degassing from 2010 to 2013. This degassing has been accompanied by intense seismovolcanic activity in form of nearly continuous tremors that were recorded by a temporary network of seismographs. To better understand the relationship between the volcanic degassing and seismic signals, we analyze here three months of continuous seismic data of 15 stations operated in 2013 using the network covariance matrix approach. We identified a high-coherence seismovolcanic tremor in the 0.5–5 Hz frequency band and examined its temporal variations by analyzing the spectral width of the covariance matrix. Tremor sources were located and clustered based on the first eigenvectors of the covariance matrix. We identified three sequential tremor source clusters active throughout the observation period. Most of tremor sources were located beneath Gorely within the volcanic edifice, above 1 km depth. A small group of sources located at depths up to 3 km below sea level is aligned along a nearly vertical conduit-like structure. When the seismic activity switched from cluster 1 to cluster 3 in mid-October 2013, the tremor sources were slightly shifted toward northeast. During the period of cluster 1 (before October 15, 2013) the peaks of low tremor coherence coincided with the precipitation. Based on the frequency distribution of high-coherence signals, source locations and volcanological observations, we suggest that the tremor activity is controlled by complex gas dynamics within the volcano and its interaction with infiltrating meteoric fluids in Gorely's conduit system.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"468 ","pages":"Article 108452"},"PeriodicalIF":2.3,"publicationDate":"2025-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145159447","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}